JPS62666A - Idling controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce rotation fluctuation and vibration of an engine due to based on the difference between explosive forces of respective cylinders by increasing or decreasing the correction value of ignition timing in each cylinder by a predetermined amount and correcting the control value of ignition timing set according to the engine running condition with each correction value in each cylinder for firing. CONSTITUTION:Correction values for correcting ignition timing in respective cylinders are given to detect the actual idle rotational frequency in explosion stroke after ignition in each cylinder. This is compared with the desired idle rotational frequency to increase or decrease the correction valve of ignition timing in each cylinder by a predetermined amount such that the actual idle rotational frequency approaches the desired one (by an integrating control means D). And in the next ignition, the control valve of ignition timing is corrected by that correction value for ignition (by an ignition timing correction means E). Thus, the rotation fluctuation and vibration of an engine in idling can be substantially reduced by correcting the ignition timing in each cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an idle control device for an internal combustion engine for an automobile.

<Prior Art> As a conventional idle control device for an internal combustion engine, there is, for example, one described in Japanese Patent Publication No. 5B-57623. An idle control valve is installed in the auxiliary air passage that bypasses the throttle valve, and a control means using a microcomputer controls the opening of the idle control valve to set the engine's idle speed to a target according to the engine cooling water temperature, etc. Feedback control is performed on the idle rotation speed.

<Problems to be Solved by the Invention> Incidentally, in such a conventional idle control device, the following feedback loops (1) to (2) are repeated.

■ Idle rotation speed detection ■ Comparison with target idle rotation speed (deviation calculation) ■ Control output to idle control valve according to deviation ■ Idle control valve operation ■ Change in intake air amount ■ Explosive force change (torque change) - Idle rotation Number changes Here, ■~■ can be detected and calculated instantly, and the operation delay for ■ is negligible, but ■,
■The process takes a considerable amount of time.

For this reason, there is a problem in that the feedback integration time has to be delayed and even minute fluctuations in idle rotation cannot be absorbed (feedback).

Therefore, in Japanese Patent Application No. 58-229825, the present applicant focused on the fact that the torque can be changed in a responsive manner by advancing or retarding the ignition time quotient, and the present applicant has focused on the fact that the torque can be changed in a responsive manner by advancing or retarding the ignition time quotient. We have proposed a system in which the idle speed is feedback-controlled by correcting the timing.

However, each cylinder - depending on the deviation from the target idle speed -
With the standard ignition timing correction control, there are differences in explosive power between cylinders due to differences in compression ratio, fuel distribution, intake efficiency, etc., so it is not possible to reduce rotational fluctuations between cylinders and engine vibrations caused by them. Ta.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an idle control device using ignition timing correction control that can reduce rotational fluctuations and engine vibrations during idle based on differences in explosive power between cylinders. .

Means for Solving the Problems> In order to achieve the above object, the present invention, as shown in FIG. An idle rotation speed detection means B detects the number of idle rotations, a comparison means C compares the idle rotation speed detected for each cylinder with the target idle rotation speed, and the idle rotation speed detected based on the comparison result is set as the target idle rotation speed. Integral control means increases or decreases the ignition timing correction value for each cylinder by a predetermined amount in order to bring it closer to An ignition timing correction means E outputting to the device F is provided.

In the above configuration, each cylinder has a correction value for correcting the ignition timing, and the actual idle speed during the explosion stroke after ignition is detected for each cylinder, and this is used as the target idle speed. By comparison, the ignition timing correction value for each cylinder is increased or decreased by a predetermined amount so as to approach the target idle rotation speed, and the next time ignition is performed, the ignition timing control value is corrected using the correction value.

In this way, by correcting the ignition timing for each cylinder, it is possible to significantly reduce rotational fluctuations during idling and reduce engine vibration.

<Example> An embodiment of the present invention will be described below.

In FIG. 2, the engine 1 includes an air cleaner 2°, an intake duct 3. Throttle chamber 4 and intake manifold 5
Air is inhaled through.

An air flow meter 6 is provided in the intake duct 3 and outputs a voltage signal corresponding to the intake air flow rate. The throttle chamber 4 is provided with a throttle valve 7 that operates in conjunction with an accelerator pedal (not shown) to control the flow rate of intake air. An idle switch 8 is attached to the throttle valve 7 to detect its fully open position. Further, an auxiliary air passage 51 is provided to bypass the throttle valve 7, and an idle control valve 52 is interposed in this auxiliary air passage 51. The opening degree of the idle control valve 52 is controlled by a signal from the same or a different unit from the control unit 30, which will be described later. The opening degree is controlled to feedback control the rotation speed to the target idle rotation speed. The intake manifold 5 is provided with a fuel injection valve 9 for each cylinder, which is opened by a drive pulse signal from the same or different unit as a control unit 30 (described later), and is fed under pressure from a fuel pump (not shown) to a pressure regulator. Fuel controlled to a predetermined pressure is injected and supplied to the engine 1.

Each cylinder of the engine 1 is provided with an ignition plug 10, to which a high voltage generated by an ignition coil 11 is sequentially applied via a distributor 12, thereby igniting a spark and igniting the air-fuel mixture. Burn it. Here, the ignition coil 11 has a power transistor 3 attached thereto.
The timing of high voltage generation is controlled through the Therefore, the ignition timing is controlled by controlling the on/off timing of the power transistor 13 using an ignition signal from a control unit 30, which will be described later. “The distributor 12 is equipped with a photoelectric crank angle sensor 1.
4 is built-in. The photoelectric crank angle sensor 14 is
It consists of a signal disk plate 16 that rotates together with the distributor shaft 15, and a detection section 17.

The signal disc plate 16 is formed with 360 slits 18 for position signals (1° signal) and, in the case of a 4-cylinder engine, 4 slits 19 for reference signals (180° signal). One of the reference signal slits 19 is also used to identify the magnetic single cylinder. The detection unit 17 detects these slits 18 and 19 and generates a reference signal including a position signal (720 position signals from 360 slits 18 per revolution of the distributor shaft 15) and a discrimination signal for IVkL 1 cylinder. Outputs . Here, the engine speed can be calculated by measuring the period of the reference signal.

Therefore, the crank angle sensor 14 constitutes a part of the means for determining the ignition cylinder, and also constitutes a part of the means for detecting the engine speed (including the idle speed).

In addition, a neutral switch 22 that detects the neutral position of the transmission, a vehicle speed sensor 23 that outputs a pulse signal with a period corresponding to the vehicle speed, and the like are provided.

The air flow meter 6, the idle switch 8° and the crank angle sensor 14. Signals from the neutral switch 22 and vehicle speed sensor 23 are input to a control unit 30.

The control unit 30 is configured as shown in FIG. 31 is a CPU, 32 is an address decoder, 33 is a ROM, and 34 is a RAM.

Among the input signals to the CPU 31, the voltage signal from the air flow meter 6 is an analog signal, so it is input via the analog input interface 35 and the A/D converter 36. Each on/off signal from the idle switch 8 and the neutral switch 22 is input via the digital input interface 37. A position signal and a reference signal from the crank angle sensor 14,
The pulse signals from the vehicle speed sensor 23 are input via waveform shaping circuits 38 and 39, respectively.

Here, the CPU 31 receives various input signals and the ROM 33 and RAM 3 according to the program on the ROM 33.
The optimal ignition timing (ignition advance angle ADV) is determined by arithmetic processing based on the data on 4, and an ignition signal is sent to the power transistor 13 for driving the ignition coil 11 via the driver 40 at that timing.

Specifically, first, the ignition advance angle ADV, which is predetermined according to the engine speed N and the load, is searched from a map in the ROM 33. Note that the basic fuel injection amount Tp (=K·Q/N, which is a constant) of the fuel injection valve 9 calculated from the intake air flow rate Q and the engine speed N is used as the load. Next, the search value of the ignition advance angle ADV is corrected as necessary to determine the final ignition advance angle ADV. When the ignition advance angle ADV is determined, if the reference signal from the crank angle sensor 14 is output at, for example, 70' before compression top dead center,
After setting (70-ADV) in the counter and inputting the reference signal, the count value is subtracted by one each time a 1゛ position signal is input, and when the count value reaches O, An ignition signal is output to the power transistor 13 via the driver 40.

When controlling the ignition timing, the ignition timing is corrected to reduce rotational fluctuations and engine vibrations during idling.

Ignition timing control including idle control is performed according to the flowchart in FIG.

The flowchart in FIG. 4 will be explained. Note that this flow is executed in synchronization with the reference signal from the crank angle sensor 14 during the arithmetic processing period shown in FIG. Further, the following is a case of 4 cylinders, and the 4 cylinders of fish 1 to 11h represent the ignition order.

In step 1 (Sl in the figure), the crank angle sensor 14
Measure the period of the reference signal from.

In step 2, the engine rotation speed N, which is determined as the reciprocal of the reference signal period, is detected based on the measured reference signal period.

In step 3, it is determined whether the computer is in an idle state.

This idle determination is performed by the idle switch 8. which is turned on when the throttle valve 7 is in the fully closed position. A neutral switch 22 that is turned on when the transmission is in the neutral position.
This is done based on the signal from the vehicle speed sensor 23 that detects the vehicle speed, and when the idle switch 8 is on and the neutral switch 22 is on, and when the idle switch 8 is on and the vehicle speed detected by the vehicle speed sensor 23 is below a predetermined value. At this time, it is determined that the computer is in an idle state, and the process proceeds to step 4. If the state is not idle, the process advances to step 18.

In step 4, the deviation ΔN between the detected engine rotation speed N and the target idle rotation speed Ns, which is predetermined according to the engine water temperature and set with correction as necessary, is calculated.

In step 5, the previous ignition cylinder is determined.

This is performed based on the generation of the reference signal for determining each cylinder and the number of subsequent generation of reference signals, which are stored. Here, referring to FIG. 5, if the current time is the calculation processing period T2 immediately after the reference signal REF 2 following the reference signal REF 1 for determining the 1st cylinder, it is determined that the previous ignition cylinder is the 1st cylinder. It is determined.

This portion, together with the crank angle sensor 14, corresponds to means for determining the ignition cylinder. Then, based on this determination, the process branches to steps 6 to 9, and ΔN in the previous ignition cylinder is determined.

That is, as in the above example, the current calculation processing period is T.
In the case of 2, it is determined that the previous ignition cylinder was the 1st cylinder, and the process proceeds to step 7.

In this way, in steps 6 to 9, after the explosion stroke of one cylinder is almost completed, the deviation between the actual idle speed and the target idle speed during that stroke is determined. This part corresponds to the comparison means.

For example, in step 5, the previous ignition cylinder! When it is determined that there are 11 cylinders, the deviation ΔN is determined in step 7.

If ΔN>O, in step 12, the integral correction value IADVI of the ignition advance angle for the NfL 1 cylinder is increased by a predetermined amount (for example, 1°). Conversely, if ΔN<O, in step 13, the integral correction value IAD of the ignition advance angle for Arashi 1 cylinder is determined.
Decrease VI by a predetermined amount (for example, 1°). This part corresponds to the integral control means.

Generally, the ignition timing at idle is not at the optimum ignition timing MBT (for example, 40 to 50 degrees before top dead center), but at MBT.
Since it is on the retarded angle side (for example, 30 degrees before top dead center) than BT, if the ignition timing is corrected to the advanced side, the torque will increase, and if the ignition timing is corrected to the retarded side, the torque will decrease.

Therefore, for example, if the actual idle speed of the first cylinder is smaller than the target idle speed, the integral correction value IA
By increasing DV1, the next ignition advance angle ADV is increased, that is, the ignition timing is advanced, and the torque is increased, thereby reducing the difference between the idle rotation speed of each cylinder and the target idle rotation speed.

In the opposite case, the integral correction value IADVI is decreased, the next ignition advance angle ADV is decreased, that is, the ignition timing is delayed, and the torque is decreased, thereby increasing the idle speed of each cylinder and the target idle speed. decrease the difference between

Next, in step 18, the engine speed N,
The ignition advance angle ADV is set by searching from the basic fuel injection amount 'rp.

Next, in step 19, the current ignition cylinder is determined. Here, if the current calculation processing period is T2 as in the above example, it is determined that the current ignition cylinder is the lk2 cylinder. Further, when the current calculation processing period is TI', it is determined that the current ignition cylinder is the magnetic one cylinder. This part also corresponds to the means for determining the ignition cylinder.

Then, based on this determination, the process branches to steps 20 to 23, and the integral correction values IADV1 to IAD corresponding to the ignition cylinder are
Correct the ignition advance angle ADV with V4.

That is, if the current calculation processing period is T2, the current ignition cylinder is the 2-cylinder cylinder, so the process advances to step 21 and the ignition advance angle ADV set in step 18 is already determined and stored. Integral correction value I for two cylinders
ADV2 is added to correct the ignition advance angle ADV. Further, if the current calculation processing period is T+", the current ignition cylinder is the Arashi 1 cylinder, so the process proceeds to step 20, and the ignition advance angle ADV set in step 18 is already set in the calculation processing period T1. The ignition advance angle ADV is corrected by adding the determined and stored integral correction value IADVI for the affected cylinder.This portion corresponds to the ignition timing correction means.

Thereafter, in step 24, the ignition advance angle ADV is set in the above-mentioned counter, and ignition is performed at the ignition advance angle.

Idle control using such ignition timing correction control effectively works from the explosion caused by the ignition, so it not only significantly improves responsiveness and control speed, but also corrects the ignition timing for each cylinder to prevent each explosion. Since the idle speed of each cylinder due to power is brought closer to the target idle speed, it is possible to deal with variations in characteristics between cylinders, reducing fluctuations in idle speed between cylinders and reducing engine vibration. This can further improve idle stability.

Further, the idle control based on the ignition timing correction control for each cylinder according to the present invention may be used in combination with the conventional idling speed feedback system '4B (ISO) based on the auxiliary air amount control.

FIG. 6 shows the experimental results by the present inventors, in which (a) shows the idle rotation fluctuation in the conventional case, and (b) shows the idle rotation fluctuation in the case of idle control by cylinder-specific ignition timing correction control according to the present invention. , and a considerable effect was confirmed.

<Effects of the Invention> As explained above, according to the present invention, it is possible to reduce rotational fluctuations and engine vibrations during idling, and to greatly improve idling stability.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram showing the configuration of the present invention, Fig. 2 is a system diagram showing an embodiment of the invention, Fig. 3 is a hardware configuration diagram of the control unit, and Fig. 4 is a flow chart showing control contents. , FIG. 5 is a time chart showing control timing, and FIG. 6 is a diagram showing the effect of reducing idle rotation fluctuation according to the present invention.゛ 1... Engine 10... Spark plug 11...
・Ignition coil. 12...Distributor 13...Power transistor 14...Crank angle sensor 30.
...Control unit patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima 2nd rM

Claims (1)

[Claims] In an internal combustion engine in which a control value for ignition timing by an ignition device is set according to engine operating conditions and output to the ignition device, a means for determining the ignition cylinder and an actual idle rotation speed during the explosion stroke for each cylinder are provided. an idle rotation speed detection means for detecting the idle rotation speed; a comparison means for comparing the idle rotation speed detected for each cylinder with a target idle rotation speed; and a comparison means for comparing the idle rotation speed detected by the comparison means with the target idle rotation speed. an integral control means for increasing or decreasing the ignition timing correction value for each cylinder by a predetermined amount in order to bring it closer to the ignition timing; An idle control device for an internal combustion engine.